Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!bellcore!faline!thumper!ka9q.bellcore.com!karn
From: karn@ka9q.bellcore.com (Phil Karn)
Newsgroups: sci.space.shuttle
Subject: Re: "Walking"
Message-ID: <1372@thumper.bellcore.com>
Date: 27 Oct 88 23:00:13 GMT
References: <665@sas.UUCP>
Sender: news@thumper.bellcore.com
Reply-To: karn@ka9q.bellcore.com.UUCP (Phil Karn)
Organization: Home for Burned-out Hackers
Lines: 13

The phenomenon you call "walking" is easily seen on any shuttle launch when
the westward-looking camera is used (the one that shows the wings edge-on).

The northward (rightward, as seen from this camera angle) "walk" is caused
by the shuttle's center of mass not being aligned directly above its thrust
vector for the first few seconds of flight.  This is a designed-in
phenomenon, though I'm not sure why.  You will note water "rainbirds" on the
top of the launcher platform; these cool the platform when the shuttle's
plumes hit it during its northward walk. Perhaps the walk was intentional, to
spread out the impact of the plumes during launch, lessening damage to any
one part of the pad.

Phil